Diagnostic circuitry for monitoring and mitigating electromagnetic interference (EMI) in an implantable pulse generator

Abstract

A system and method for measuring, monitoring and mitigating EMI interference in an implanted stimulation lead system associated with an IPG. A Kelvin connection scheme operative with a diagnostic circuit is provided for sensing an interference voltage induced at a Kelvin connect electrode of the lead system, wherein the diagnostic circuit is configured to generate one or more control signals for adjusting in substantially real time a common-mode voltage reference provided to supply a biasing voltage to the IPG circuitry.

The invention claimed is: 
     
       1. A method of mitigating electromagnetic interference (EMI) in an implantable medical device (IMO) having a pulse generator configured to supply stimulation to tissue of a patient, the method comprising:
 monitoring an interference voltage sensed at a Kelvin connection node associated with an implantable lead system of the IMO; and 
 generating one or more control signals to adjust a common-mode voltage reference output by a charge pump voltage source of the IMO depending on a difference between the common-mode voltage reference and the interference voltage sensed at the Kelvin connection node, wherein the one or more control signals comprise at least a first control signal generated responsive to determining that the interference voltage is greater than the common-mode voltage reference by a first threshold, the first control signal comprising a control signal operative to decrease the common-mode voltage reference output of the charge pump voltage source. 
 
     
     
       2. The method as recited in  claim 1 , wherein the one or more control signals comprise at least a second control signal generated responsive to determining that the interference voltage is less than the common-mode voltage reference by a second threshold, the second control signal operative to increase the common-mode voltage reference output of the charge pump voltage source. 
     
     
       3. The method as recited in  claim 2 , wherein the first control signal and the second control signal comprise 1-bit digital control signals. 
     
     
       4. The method as recited in  claim 2 , wherein the first and second thresholds are a same value. 
     
     
       5. The method as recited in  claim 2 , wherein the interference voltage is induced due to least one of a magnetic resonance imaging (MRI) of the patient and an electromagnetic interference (EMI) event encountered by the patient. 
     
     
       6. The method as recited in  claim 2 , further comprising configuring at least one active electrode of the implantable lead system as one of a cathode to provide cathodic stimulation to the patient's tissue and an anode to provide anodic stimulation to the patient's tissue with respect to a particular therapy application. 
     
     
       7. The method as recited in  claim 6 , wherein the particular therapy application comprises a therapy selected from at least one of a spinal cord stimulation (SCS) therapy, a neuromuscular stimulation therapy, a dorsal root ganglion (DRG) stimulation therapy, a deep brain stimulation (DBS) therapy, a cochlear stimulation therapy, a drug delivery therapy, a cardiac pacemaker therapy, a cardioverter-defibrillator therapy, a cardiac rhythm management (CRM) therapy, an electrophysiology (EP) mapping and radio frequency (RF) ablation therapy, an electroconvulsive therapy (ECT), a repetitive transcranial magnetic stimulation (rTMS) therapy, and a vagal nerve stimulation (VNS) therapy. 
     
     
       8. The method as recited in  claim 2 , further comprising configuring at least one of an inactive electrode of the implantable lead system, an unused sense capacitor terminal of an active electrode of the implantable lead system and an EMI antenna as the Kelvin connection node.